1. Field of the Invention
The present invention relates to a toner conveying device, a process cartridge, and an image forming apparatus.
2. Description of the Related Art
In electrophotographic image forming apparatuses, such as copiers, printers and facsimile machines, a latent image is formed on a photosensitive element, and is developed into a visible image with toner. Toner not used in developing the latent image remains on the photosensitive element as waste toner. Generally, such image forming apparatuses include a container for waste toner as well as one for fresh or new toner to be supplied. In recent years, from a viewpoint of space saving, a toner cartridge (toner bottle) has been proposed that is originally a fresh-toner container but serves also as a waste-toner container.
Japanese Patent Publication No. S63-10424 discloses a conventional technology related to a toner cartridge including a developer hopper, at a lower opening of which a developing roller is arranged. The toner cartridge is filled with toner, with a little space left at an upper portion. The space is separated from the developer hopper by a flexible partition, and has a toner collecting hole on a side wall. Waste toner is collected by a cleaner, and is conveyed by a toner conveying member located between the cleaner and the toner collecting hole into the space through the toner collecting hole. As fresh toner reduces with use, the flexible partition moves downward, and the space at the upper portion gradually increases. Waste toner is accumulated in this increasing space.
Japanese Patent Application Laid-Open No. H5-88549 discloses a conventional technology related to a developing device provided with a unit that integrally including a toner hopper that contains fresh toner to be supplied and a waste-toner container that contains waste toner collected from an image carrier. The toner hopper is separated from the waste-toner container by a partition made of flexible material to be deformable at least toward a toner hopper side.
Japanese Patent Application Laid-Open No. H11-153901 discloses a conventional technology related to a toner cartridge that integrally includes a fresh-toner container and a waste-toner container. The waste-toner container is arranged above the fresh-toner container, and separated from the fresh-toner container by a partition. The partition is made of flexible material so that it can deform towards the fresh-toner container.
However, with the conventional technologies, a stirring member and the like increases the internal pressure of the space containing toner. As a result, the flexible partition expands instead of hanging down, and contacts a waste-toner conveying screw to convey waste toner, thereby increasing torque or being caught in the screw.